Concentric JTE Design for High Breakdown Voltage in Silicon Carbide Devices
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Summary
Problems
The challenge in silicon carbide semiconductor devices is to achieve a stable termination structure that provides high breakdown voltage, as existing junction termination extension (JTE) structures face limitations due to electric field concentration and impurity concentration gradients, making it difficult to reduce manufacturing costs and improve breakdown voltage performance.
Innovation solutions
A semiconductor device with a concentric JTE structure featuring alternating p-type regions of varying widths and impurity concentrations, including an intermediate region with a gradual impurity concentration gradient, to relax the electric field and enhance breakdown voltage.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a conventional JTE structure with p-type high-concentration region and p-type low-concentration region is used, then the electric field is relaxed on the outer peripheral portion of the p-type high-concentration region, but the breakdown voltage is limited by avalanche breakdown in the outer peripheral portion of the p-type low-concentration region
Why choose this principle:
The termination structure is divided into multiple concentric regions with different impurity concentrations: a first p-type region with first impurity concentration, a second p-type region with second impurity concentration lower than the first, and a third p-type region with third impurity concentration lower than the second. This segmentation distributes the electric field relaxation function across multiple zones, preventing avalanche breakdown in a single low-concentration region while maintaining high breakdown voltage.
Principle concept:
If a conventional JTE structure with p-type high-concentration region and p-type low-concentration region is used, then the electric field is relaxed on the outer peripheral portion of the p-type high-concentration region, but the breakdown voltage is limited by avalanche breakdown in the outer peripheral portion of the p-type low-concentration region
Why choose this principle:
Each concentric region is assigned a specific impurity concentration tailored to its location and function. The first p-type region near the active region has higher impurity concentration for strong field control, while outer regions have progressively lower concentrations for gradual field relaxation. This local optimization of impurity concentration profiles resolves the contradiction between field relaxation and breakdown voltage limitation.
Application Domain
Data Source
AI summary:
A semiconductor device with a concentric JTE structure featuring alternating p-type regions of varying widths and impurity concentrations, including an intermediate region with a gradual impurity concentration gradient, to relax the electric field and enhance breakdown voltage.
Abstract
A semiconductor device, including a substrate of a first conductivity type, an active region and a termination structure portion formed on a front surface of the substrate, and a plurality of regions of a second conductivity type formed concentrically surrounding the periphery of the active region in the termination structure portion. Each region has a higher impurity concentration than one of the regions adjacent thereto on an outside thereof. The plurality regions include first and second semiconductor regions, and an intermediate region sandwiched between, and in contact with, the first and second semiconductor regions, and a third semiconductor region. The intermediate region includes a plurality of first subregions and a plurality of second subregions that are alternately arranged along a path in parallel to a boundary between the active region and the termination structure portion, the second subregions having a lower impurity concentration than the first subregions.